Forming filaments out of viscose or similar viscous material.



UNITED sT iEs PATENT oFFioE.

CHARLES A; ERNST, OF LANSDOWNE, PENNSYLVANIA, ASSIGNOB, TO SILAS W. PETTIT, OF PHILADELPHIA, PENNSYLVANIA,

No. scenes.

Specification of Letters Patent.

Patented Aug. 20, 1907.

Application filed April 27, 1907. Serial No. 370,537.

To'all whom it may concerii:

.Be it known that 1, (inputs A. ERNST, a citizen of the United States, and a resident of Lansdowne, State of Pennsylvania, have invented certain new and-useful Improvements in Forming Filaments Out of Vis cose or Similar Viscous Material, of which the followving is a full, clear, and -xuct' description.

My invention relates to the'metliod of forming filaments of cellulose from viscose or similar viscous material and more particularly to the production of the viscose itself, the objects of my invention being to shorten the time of stora-goheretofore required for the.

production of viscose, suitable for the formation of filaments, and to preserve the same, to produce a viscosewhich is speedily coag ulated when ejected from the spinneret in'to the fiicingJoat-h, and to increase the strength and elasticity of the filament finally formed.

In making filaments out .of viscose, or similar vis cons substances, a cellulose base, which maybe .wood

pulp, cotton or other suitable form ofcellulose is 1 subjected to the action of asolution of caustic soda forasuitable length of time (1 to 4 days) as a result of which the pulp or cotton is changed into soda-cellulose. This product, soda-cellulose, is then placed in a xantliizing machine, comprising. a closed receptacle; provided with any suitable, means for-thoroughly agitating the contents thereof, and a suitable quantity of v carbon bi-sulfid is added. The Xanthizing machine is then set in motion and the. contents thoroughly stirred or agitated, whereupon the soda-cellulose,- which is relatively insoluble in water, caustic soda,

and similar solutions is changed into a substance commonly known as cellulose-Xanthate, which is still solid but which is soliible in the said solutions. To

' the cellulose xanthate is then added a suitable quailtity of one of the above said solvents for the same and a viscous liquid, commonly known as viscose is produced. A filament is then formed from theviscose byejecting the viscose through minute apertures in 40a spinneret into a coagulating or neutralizing bath,

the function of which. is to neutralize the caustic soda inthe viscose and to precipitate the xanthate.

Freshly formed viscose would be coagulated and .i transformed intocellulose by eje ctingit through a must be ejected into a weak neutralizing bath, or in other words it necessary to employer producea viscose which will coagulate immediately into a fila;

ment when it is ejected into a weak neutralizing bath.

Heretofore, in ordeii to produce a viscose from which filaments can be spun commercially, it has been necessary to allow the freshly formed viscose to stand or age in storagerecept-acles. It is well known, however, by. those skilled in the art, that if the viscose formed in the manner above described, (that is to say by dissolving the cellulose xanthate in a suitable solvent) be allowed to stand or -age for a sufiicient length of time it will of itself change or coagulate, it

will be apparent that'the function of the aging process is to allow the viscose to approach but not 'quite reach that critical point at which it of itself coagulates, so that all that is needed to transform it into a filament is to spin it into a weak neturalizing bath. But on account of the fact that itis impossible to obtain absolutely uniform cellulose xanthate by the xant-hizing process,- the result is that during the 7 aging" process certain portions or parts of the viscose will age too much; and particles will frequently coagulate and change into dark colored compounds, which greatly interfere with the spinning by clogging the minute apertures in the spinneret and therefore materially depreciate the quality of the threads or filaments produced. This coagulating of parts of the viscose appears to be due to the further action of carbon bi-sulfid upon the cellulose during the aging process. Moreover during the time required for the aging, the discoloringimpurirties in the,viscos e conl r stantly increase, on account of the formation of sodiumt of a neutral salt in the solvent for the cellulose xanthate,

before the cellulose Xanthate is added thereto. In other words I dissolve"cellulose xanthate in a solution of caustic soda or ofany other suitable solvent gpntaining a soluble salt.v I have found that the salts of sodium are particularly adapted to my purpose and I may use sodium-carbonate, sodium-sulfite, sodium-silicate or any other similar salts, since they impart-to the viscose e "theproperty of coagulating immediately when ejected into a weak neutralizing bath.

Thesecond object, namely, that of checking the further action of the carbon bi-sulfid upon the cellulose and to combine with those impurities in the viscose,

which would otherwise discolor the same, is accomplished by adding to the solvent for the cellulose xanthate a suitable quantity of a neutral salt, prefer the viscose and is 'not so expensive as to make the process commercially impracticable.

Another advantage of using sodium sulfite as the salt which is added to the solvent, is that it introduces into the setting or coagulating hath no new chemical element and makes it comparatively easy to reclaim any of the by-products or agents after they have become exhausted, without any diflicult or unusual manipulation I or'processes, although the addition of any other suitable neutral salt or combination of salts, which will produce theresults above set forth, may be substituted therefor I as theyare fully within the scope and aim of my invention. I do not wish, however, to limit myself to a 00- v agulating or neutralizing bath composed of a solution of sodium bi-sulfite sincea solutionof ammonium chlorid -or ammonium sulfate, or a weak solution of almost any other acid may be employed with satisfactory results.

The action of the weak acid bath upon the viscose is merely to transform the liquid cellulose xanthate into a solid filament of cellulose xanthate; that is to say it merely c'oagulates the viscose into a thread or filament.

order to complete the transformation of the viscose into cellhl ose or artificial silk, these filaments after being wound upon spools in any suitable manner, are immersed in a bath of sodium bi-sulfite and allowed to stand for a considerable length of time After this the threads are washed and dried and spun together in any of the usual and well known methodsof spinning filaments.

While I have described one way in which my process of forming filaments out of viscose may be per- 40 formed, I do not'desire to be construed as being limited to such, inasmuch as my invention contemplates the introduction into the viscose of any suitable agent or agents, the action of which is to render fresh viscose suitable for spinning and to. prevent the undesirable effects of a continued action'oi carbon bisulfid upon the cellulose.

Having thus described my invention what I claim States is: v

and desire to protect by Letters Patent of the United 1. The process of forming viscose for the production of cellulose filaments, which consists in treating soda' cellulose withrcarbon bi-sulfid to form cellulose xanthate and then dissolving the said 'xanthate in a solution containing a substance which will prevent the further action of thecarbon'bi-sul fid on the cellulose.

2. The process. of forming viscose forthe production of cellulose filaments which consists in treating soda-cellulose with carbon bl-sulfid and forming cellulose kanthate andthen dissolving the said xanthate in a solution conand then ejecting com day of April, 1007'.

taining a substance which will cause the said viscose to coagulate under the action of a'wenk neutralizing solution.

3. The process of forming viscose for the production of cellulose filaments. which consists in dissolving cellulose xanthate in a solution containing a substance which will cause the viscose. soformed. to coagulate rapidly under the action of a weak neutralizing solution. 4

4. The process of forming viscose for the production of filaments which consists in adding to a solvent for celhr lose xanthate, a salt which will cause the immediate coagulation of the resulting viscose upon its contact with a weak neutralizing solution.

The process of forming a filament which consists in forming cellulose Xanthate and dissolving the same in an alkaline solvent to which has been added a neutral salt, the resulting viscose into :1 weak neutralizing bath through minute apertures.

(i. The process of forming a filament of cellulose which consists in changing cellulose to soda-cellulose. changing soda-cellulose to cellulose vanlhnte. dissolving the cellulose xnnthate in an alkaline solvent containing sodiumsoda-cellulose to cellulose xanthnte, dissolving the said xanthntein a solution containing: a sulfite and then congulating the viscose so formed by ejecting it -into a weak neutralizing bath. 7 v

10. The process of forming a filament of cellulose which consists in changing cellulose to soda-cellulose, changing the soda-cellulose 'to cellulose xanthate, dissolving, the

cellulose xanthate in an alkaline solvent containing sodium-sulfite. then coagulating the viscose so formed by ejecting it into a weak acid bath, and then subjecting the filament to the continued action of a weak acid bath.

11. The process of forming a filament, which consists. in subjecting cellulose to the action of caustic soda .to

produce sodmcellulcse, then adding carbon'bi-sulfid to. the

vsoda-cellulose to 'form cellulose xanthate, and then dis-' solving the said cellulose .xanthate in a solution composed of a solvent for the xanthate and sodium-sulfitc.

12. The process of forming a filament of cellulose which consists in dissolving cellulose xnnthate in an alkaline solvent containing sodium-sulfite, then coagulating the viscose so formed by ejecting it into a bath composed of the solution of sodium bi-sulfite and then subjecting the filament to 'the continued action of a weak solution of sodium bi-sulfite.

13. The process of forming a filament of cellulose which consists in dissolving cellulose xanthate in a weak solutime to completely change the .coagulnted viscose into cellulose.

In witness whereof, I have hereunto set my hand this CHARLES A. ERNST. "Witnesses: I

AnsToN B. Mourxroir, ALnxANnr-in Luck. 

